India, the land of golden summers and clear blue skies, is quietly losing its sunlight. A comprehensive scientific analysis titled Long-term trends in sunshine duration across India (1988–2018) has revealed a steady and widespread decline in sunshine hours across the country. Conducted by researchers from Banaras Hindu University, the Indian Institute of Tropical Meteorology (Pune), and the India Meteorological Department, the study found that the northern plains are witnessing the steepest annual drop of around 13 hours each year, while regions like the Himalayas, the west coast, and the Deccan plateau are also seeing significant reductions.The findings point to rising air pollution as a key driver behind this dimming effect. Aerosols from industrial emissions, vehicle exhaust, and crop residue burning are scattering and absorbing sunlight before it reaches the ground. Combined with increased cloud cover during monsoon months, these factors are reducing India’s overall sunshine exposure. Scientists warn this ongoing decline could impact solar power generation, crop productivity, and long-term environmental stability.
Decline in sunshine hours in India varies across regions
According to the study, sunshine hours have been dropping across almost every major region of India between 1988 and 2018. The northern plains recorded the sharpest annual decline, losing about 13 hours of sunlight. every year. The Himalayan region followed closely with an average fall of about 9.5 hours annually. The western coast lost around 8.6 hours, central India about 4.7, and the Deccan plateau around 3.1.Interestingly, the northeastern states were relatively stable compared to other parts of the country. Researchers observed that these regions maintained a consistent sunshine pattern over the decades, possibly due to their unique climatic conditions and lower levels of industrial pollution.On a monthly scale, most regions saw more sunshine between October and May and less during the monsoon months. However, in the Himalayan and northern inland areas, the trend reversed due to distinct weather patterns influenced by altitude and seasonal winds.
Causes behind the decline in sunshine hours in India
The researchers identified two major factors contributing to the country’s dimming skies: air pollution and cloud cover.Air pollution and aerosols: Industrial activities, urbanization, and vehicular emissions have significantly increased the amount of particulate matter in the atmosphere. These aerosols scatter and absorb incoming solar radiation, reducing the amount of direct sunlight reaching the surface. Over time, this leads to a measurable reduction in daily sunshine duration. Additionally, persistent exposure to polluted air can alter local climate patterns, impact human health, and contribute to long-term changes in atmospheric visibility and temperature regulation.Increased cloud cover: The study also found that cloudiness during monsoon months has intensified in several regions. Heavier and more persistent cloud layers act as a barrier to sunlight, compounding the dimming effect caused by aerosols. Together, pollution and cloud cover have created a long-term trend of lower solar irradiance across the Indian subcontinent.
Impact of declining sunshine hours in India on energy and environment
The decline in sunshine hours poses serious challenges for India’s renewable energy goals. The country has set ambitious targets for solar power capacity, but reduced sunlight could affect solar panel efficiency and energy output. Even a small drop in solar radiation can impact energy generation, especially in northern and western India, where solar farms are expanding rapidly.Agriculture, too, could feel the effects. Many crops rely on consistent sunlight for growth and productivity. Prolonged dimming can reduce photosynthesis rates and alter crop cycles, affecting yields in key agricultural belts.The environmental impact extends further. Reduced solar energy at the surface can change local weather patterns, influencing temperature, humidity, and rainfall. This shift may lead to changes in regional microclimates, further affecting ecosystems and water resources.
Why studying sunshine hours in India matters for the future
Tracking long-term sunshine trends is more than a climate statistic. It serves as a crucial indicator of air quality, energy potential, and environmental health. Scientists emphasize the importance of regular monitoring, expansion of meteorological data stations, and integration of satellite-based sunlight measurements.Policymakers are urged to treat the decline in sunshine hours as a sign of worsening air pollution. Controlling emissions from industry, transportation, and crop burning can help restore clearer skies and protect solar resources. Integrating sunshine duration data into future energy planning will also help ensure that solar projects remain sustainable despite changing climatic conditions.The latest findings make one thing clear: India’s skies are growing dimmer, and the trend cannot be ignored. From energy production to agriculture, the effects of reduced sunlight could ripple across multiple sectors. Scientists behind the study warn that urgent action on air pollution and sustainable urban growth is essential to slow this decline.As the country continues to invest in solar energy and climate resilience, acknowledging the shrinking sunshine hours in India is critical. Cleaner air, better land-use planning, and continued research could help the nation reclaim its light and protect the bright future it depends on.Also read| The real cause of depression may lie in just two brain cell types, scientists say
